In numerous fields of technology it is required to apply very thin layers of pure substances on particular objects. Examples of this are window panes which are provided with a thin metal or metal oxide layer to filter out particular wavelength ranges from the sunlight. In the semiconductor technology, thin layers of a second substrate are applied onto a first substrate. It is particularly important in this technology that the thin layers are not only very pure but must also be apportioned very precisely so that the particular layer thicknesses are exactly reproducible in each instance.
Thin layers can be applied by chemical or electrochemical deposition, by vapor deposition in a vacuum or by "sputtering" or cathode disintegration. In cathode sputtering a gas discharge plasma, a substance to be sputtered on a cathode and a substrate to be coated are provided in a vacuum chamber.
An arrangement for applying thin layers on a substrate by means of the cathode sputtering method is already known in which a mechanical shutter is located between a cathode to be sputtered and an anode, the shutter dividing the space between the cathode and the substrate to be coated (EP-A-0 205 028). This arrangement, however, includes no microwave irradiation.
Futhermore, an arrangement for vapor deposition with the use of plasma is known, in which electrically charged particles are generated and the electrons are brought by means of a magnet into an electron cyclotron resonance (ECR) (EP-A-0 103 461). In this arrangement the ECR excitation takes place far removed from the substrate. Moreover, the magnetic field required for the establishement of the ECR condition is generated by means of an electromagnet of large volume.
A somewhat similar arrangement to provide ECR conditions using small and movable permanent magnets, is likewise known (DE-A-3 705 666). In this arrangement, however, no cathode sputtering is provided.
Further, a sputtering installation using microwaves is known in which the microwaves are irradiated in a direction perpendicular to an imaginary line extending between the target and the substrate (EP-A-0 173 164). In this sputtering installation, in addition, magnets are provided above the target and below the substrate, with the magnetic field of one magnet penetrating the target and the magnetic field of the other magnet penetrating the substrate. Since the microwaves in this sputtering installation are not directed onto the surface of the substrate, no substrate plasma is generated which is utilized for the reactive deposition by means of sputtering.